ST STEVAL-WBC2TX70 - Figure 6. ASK Modulation; Figure 8. Example of Bit Encoding; Figure 7. ASK Timing

Figure 6. ASK modulation
Figure 7. ASK timing
The power receiver uses a differential biphase encoding scheme to modulate the data bits onto the power signal.
The STWBC2 monitors ring voltage, current, and phase, filters out the carrier wave, and demodulates the signal.
The communication itself is carried out via packets. Each packet consists of four parts and each of those parts
consists of several bits/bytes.
Each communication bit is synchronized to the power receiver’s internal 2 kHz clock signal period. A ONE bit is
encoded as two transitions of the power signal, while a ZERO bit is encoded as a single transition.
Figure 8. Example of bit encoding
UM3286
Device description and operation
UM3286 - Rev 1
page 15/84